1. Field of the Invention
The invention relates to recovery of oil. In one aspect, the invention relates to improvement of fluid communication between a well bore and an oil containing subterranean formation by removal of pipe dope constrictions. In another aspect, the invention relates to removal of pipe dope from tubulars.
2. Brief Description of the Prior Art
Pipe dopes are employed for casing and tubing connections in high pressure well service. These materials, also known as thread compounds, are described and defined in API Bulletin 5A2, Fifth Edition, April 1972. The compounds were originally developed by the Mellon Institute of Industrial Research, under an API-sponsored research project, to meet the following objectives:
(1) Adequate lubricating qualities to prevent galling in threaded connections during make-up.
(2) No tendency to disentegrate nor undergo radical change in volume at temperatures up to 300.degree. F.
(3) No tendency to become excessively fluid at temperatures as high as 300.degree. F.
(4) Sealing properties sufficient to prevent leakage at temperatures as high as 300.degree. F.
(5) Absence of any deleterious instability and of any drier or hardener that will evaporate or oxidize, thereby changing the thread-compound properties.
(6) Resistance to water absorption.
(7) Sufficient inert filler to prevent leakage of API round-thread casing and tubing joints under pressure as high as 10,000 psi.
(8) Readily applicable by brush to pipe joints in cold weather.
The term "pipe dope", as employed herein, means the compounds designated in Section 1 of API Bulletin 5A2. A quotation from Section 1 of API Bulletin 5A2 follows: